MWI: Many Worlds interpretation of quantum mechanics explained | featuring Sean Carroll

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Link to Sean Carroll's EXCELLENT new book "Something Deeply Hidden":tinyurl.com/ycdpldjp
The many worlds interpretation of quantum mechanics was put forth by graduate student Hugh Everett in 1957. It was considered preposterous at the time, but is now going mainstream. It requires us to change our paradigm about our experience of reality, and consider that there may be many worlds where every possible quantum outcome happens. And that we are living in just one of those branches of the universe at any one moment.
I spoke to the authority on this subject: Prof Sean Carroll of Caltech. That interview along with the explanation and comparison of the Many Worlds interpretation compared to the Copenhagen interpretation is featured here.
the Copenhagen interpretation was championed by Neils Bohr in the 1920’s. It suggests that objective reality doesn’t exist until it is observed or measured. The quantum world is governed by a set of probabilities as described by a wave function that evolves over time in the Schrodinger equation. The act of measuring forces the set of probabilities to randomly assume only one possible value.
But the many worlds interpretation says that the entire universe is in a state of superposition. A measurement may look like a particle has some set of properties, but that is not the overall reality. It posits that the world splits every time we THINK a quantum measurement is made. And that although we may see one thing in our world, there is another world in which another thing has occurred.
So for example, if we are trying to measure the spin state of an electron, the MWI says that our measuring device becomes entangled with the electron. This causes something called decoherence. The decoherence splits the universe in two such that in one universe the device measures spin up, and in the second universe, the device measures spin down. Both universes exist. We just happen to experience one of these universes. We could just as well be in either universe.
And similarly, this kind of decoherence is happening all the time. And in every instance this happens, the universe splits. So this is why it is called many worlds, because many such branches or splits of the world exist simultaneously.
In the Copenhagen interpretation, there are two sets of rules. One set of rules applies to systems prior to measurement, and a different set of rules applies for systems after measurement.
The many worlds interpretations says, no, this is not the way the universe works, that there are only one set of rules that abide by and evolve over time according to the Schrodinger equation. And there is no randomness because all possible outcomes are a branch of the many worlds.
The Good points about the MWI are:
1) it gets rid of measurement problem.
2) It lets us apply quantum mechanics to the entire universe.
3) there is no randomness.
The bad points about MWI are:
1) How does branching occur?
2) How is energy conserved.
3) Why do we see only one world, if the other worlds are equally present?
Branching occurs by decoherence, which is not quite like wave collapse. It can be thought of as a loss of information to the environment. When an isolated quantum system like say an electron gets entangled with its environment like photons and other molecules that may be present, this has the effect of a transfer of quantum information. All of the photons and atoms that bounce off the electron are agents of decoherence, and can fix its position in space and give it a sharp outline.
This is decoherence and causes the branching. This is how quantum systems can start behaving like classical system.
#quantummechanics
#manyworldsinterpretation
#quantumphysics
The total energy of the universe and all its branches is conserved analogous to the way that the all the individual probabilities inherent in the Schrodinger equation add up to one.
I asked Sean Carroll about that, and he, like me, hates that idea. I myself think that physics is more than calculations, it is a science that tries to get at the truth about what the true nature of reality actually is. That’s what we should really be after, I feel. And that pursuit at least on this channel will always exist.

[@ArvinAsh]

Here are a couple of additional interesting points from Sean Carroll: 1) The theoretical total possible number of universes is not infinite, but is 2^10^122 (2 to the power 10 to the power 122). It is a lot, but is not infinite. How is this number derived you ask? It is is the total possible entropy of the universe based on its observable volume. Another way to calculate it - If the entire universe was one giant black hole, this number would be its entropy! 2) Sean Carroll pointed out to me that he would NOT say, like I do in the video, that "there are no probabilities." He'd say this: "...that the *theory* is deterministic (so there is no fundamental randomness), but there is uncertainty, namely uncertainty about which branch you are on when the universe splits. Otherwise you wouldn't be able to understand what we observe, which is that quantum events are unpredictable." 3) For those of you that have more questions and for further insight, this Sean Carroll blog is excellent reading: www.preposterousuniverse.com/blog/2014/07/24/why-probability-in-quantum-mechanics-is-given-by-the-wave-function-squared/ 4) If you are intrigued and want to learn the details of quantum mechanics explained without an inordinate amount of math, grab Sean Carroll's newest book for sure! I couldn't put it down once I started reading it. www.amazon.com/Something-Deeply-Hidden-audiobook/dp/B07QT9TBQW/ref=sr_1_1?crid=3TFG0SCTFHGC9&dchild=1&keywords=something+deeply+hidden+sean+carroll&qid=1589034141&s=books&sprefix=something+deep%2Caps%2C147&sr=1-1 5) Did you see me eat the apple or the lollipop?

[@gamecoolguy619]

That value would be (potentially) correct for the observable universe not universe, people really need to have a distinction between the two. You could be born in lock down your whole life so far and only have window of reality but does that mean reality is only what you see through this window?

[@jessemontano6399]

Since photons, particles of dust, etc, causes decoherence since in essence they are monitoring everything else causing the collapse of the wave function, gravity doesn't collapse wave function?? If gravity doesn't decohere then it seems that gravity will be impossible to quantize. Wrong topic lol. Just wondering

[@ArvinAsh]

@@jessemontano6399 Gravity probably can cause decoherence, but at these scales the electromagnetic and other 3 forces overwhelm it, so gravity does not appear to have much of an influence on quantum scales.

[@Domispitaletti]

This kind of philosophical approuch will make people lose confidence in science. Take it to philosophy department that is where it belongs.

[@jakeallstar1]

@@Domispitaletti who would lose faith in science over discovering the nature of reality? That is the fundamental idea of science.

[@theraven6836]

I’m still confused, but at a much higher level.

[@aleatoriac7356]

I never had a problem with "how is energy conserved" answers to this issue, as Sean has always done a great job of answering that one. The one that I still don't understand is #3: Why do we see only one world. The "identical twin from the same zygote" is a bad example... you can see and interact with an identical twin. So on that score I'm still confused. I'm convinced Carrol has this right due to the parsimony and predictive capacity of the Everett interpretation, but I balk at the failure to make an empirically testable prediction here.

[@meandnoother]

@@aleatoriac7356 Perhaps because we are also entangled to this 'world' from the moment we were conceived. Just like how the electron becomes entangled to the light particles that hit it our cells also become entangled when any particle meets one. And for us that just happens to be this particular world, I guess that's how you should interpret it.

[@anwarulmamoon4299]

@@meandnoother I think ,there are still other theories that are needed to be discovered to complete our understanding of our existence or reality, only Quantum theory can not explain all our questions.

[@johnmcntsh]

@@aleatoriac7356 I think Sean explains as you are on another part of the wave. Once that happens you can never go back, go over, go anywhere but your area of the wave. I will try a horrible example. In the first microsecond of the fertilization of your mothers egg you are twins but in a trillionth of a second one of you is transferred to a world on the opposite side of the universe. You will never see him/her no one will ever know your twin or his/her world exists. For ever and ever. You have to look at that wave the same way only you are dealing with hilbert space .

[@aleatoriac7356]

@@johnmcntsh Thanks My layman stupidity is showing, and I think maybe my confusion stems from an intuitive mistake / thinking about this in terms of a Minkowski space. It's like I can't think "non-classically" like I'm some kind of damn NPC it sucks The only thing we have is the math, really, isn't it? No repeatable experiments. I'm always skeptical of pure deduction. But that may be the best that can be done on this particular subject.

[@christosmakariou4574]

In the other universes my other selfs get to understand this completly!

[@ArvinAsh]

Haha, I hear you brother. This is mind melting stuff! A very difficult subject.

[@Webfra14]

Sorry, but the universe branches only into physically possible variants...

[@josemanueld5413]

@@Webfra14 lol

[@shahanshahpolonium]

@@Webfra14 thats not very encouraging

[@Webfra14]

​@@shahanshahpolonium Well, luckily, what I wrote in this universe can't be seen by the other universes. And for this universe, Christos already seems to conclude he doesn't get to understand the many worlds theory... So he shouldn't be discouraged from anything he wanted to do?

[@amando96]

Pretty crazy that in another universe he ate an apple.

[@Andrew-zq3ip]

Trespasser

[@FrankCoffman]

Not only that. In the next instant, his duplicate self could be doing something different, constantly switching back and forth between various possibilities, ad infinitum. The MWI leads to chaos, no consistent progression of events.

[@benjamingamrekeli1578]

@@FrankCoffman the duplicate doesn't switch between different branches, all possibilities exist simultaniously

[@FrankCoffman]

@@benjamingamrekeli1578 ~ Yeah, I know that's the idea -- a silly idea. I didn't mean that they switch branches. The whole idea is too absurd for words -- a total fairy tale.

[@FrankCoffman]

@@benjamingamrekeli1578 ~ If a duplicate person was created, would s/he retain all the exact memory traces and traits of the original self? How and why could exact duplication possibly occur? If a duplicate self didn't have all the same memories and traits as the original, the copy would act differently than the original. Unless the copies were precisely the same, they would be inconsistent from moment to moment and would therefore behave erratically. Life would be chaos. How could exact copies be generated? The whole idea is ridiculous nonsense for a multitude of reasons, aside from being unsubstantiated and untestable.

[@taquiupa]

The problem here, I think, this theory of many worlds can never be proved and it will remain in the realm of speculation forever.

[@ArvinAsh]

Well according to Sean Carroll, the fact that the Schrodinger equation works is proof, because Many Worlds is the purest interpretation of that equation. I, like you, find this unsatisfactory.

[@LuisAldamiz]

@@ArvinAsh - That's not empirical proof.

[@mikepop4382]

​@@LuisAldamiz the universe just split again when you said that and now it is proven in that universe :-)

[@gurumage9555]

I don't think we should be carelessly splitting the universe with apps like that . Rick broke his universe that way and spawned a bunch of schrodinger's cats.

[@shahanshahpolonium]

lmao

[@ploppyploppy]

Microsoft wrote an app like that and when they launched it time stopped in a large amount of universes and they turned blue. Others tried to resolve the problem automagically before giving up and blinking out of existence.

[@gypsydoratarot8441]

😂😂😂😂

[@casualsatanist5808]

Random.org....i will split the universe in 299792458 universes every day from now on. Today were in universe 388608. Quite lucky being so low! I feel... *O M N I P O T E N T*

[@mike-Occslong]

Lol

[@esra_erimez]

What is the flavor of the lollipop that I'm watching you eat right now?

[@1SpudderR]

Esra Erimez Hmm? Flavours? Take your pick, I know what it is! NOW....But do you know what Now is.....!

[@ArvinAsh]

Haha...Cherry. Of course! Welcome, my friend from the alternate world!

[@nashdasmurayan1975]

Dammit! You beat me to it.

[@actsnfacts]

@@ArvinAsh We could make a Mandela effect practical joke! After a certain number of views, you take this version down and upload an identical one, just with the lollipop instead. When people ask about it, you tell them it has always been so... LOL

[@thedominater9023]

@@richardnedbalek1968 then I think that if you asked you are dead or alive then app would say every possibility is death😆😆😆😆😆😆😆just joking

[@colinmoffat2705]

I loved this video, I just finished Sean's book earlier this month and seeing you pop up with another amazingly detailed and open discussion about it with Sean! Amazing I don't know where I sit, I think I'm just as skeptical of both interpretations! Excited for more discoveries and human applications of QM!

[@frankfreaksout7736]

"Just shut up and calculate" lol I like how even some scientists are enjoying shutting part of their brain off, so they can continue the life they're already living, and don't have an existential crisis.

[@ArvinAsh]

This is not far fetched actually.

[@Xbob42]

That's one way to think of it. I imagine that more likely it was just a way to get people to stop trying to interject some deeper meaning into the science they're doing, thereby possibly tainting it. At least while actively doing the calculations and whatnot.

[@wecas9596]

Well said!👍

[@davidtunstall6454]

Great video Arvin, I loved listening to the interview. You would make a great podcast host.

[@ArvinAsh]

Thanks but I'm not so sure I'm cut out for this. I was a nervous wreck with Sean Carroll. Too star struck. lol.

[@alejandrobetancourt4902]

The best science teacher I ever had. You are the perfect level of advanced yet attainable.

[@Legaleze]

It truly is a bizarre subject yet you explain it so well.

[@gregoryfloriolli9031]

I’m in the same boat as you were I came in as skeptical but ended up being a little less skeptical.

[@Ron4885]

Well said Gregory. Me too.

[@MrBollocks10]

Me too ... ... Except for the second bit.

[@MagruderSpoots]

The more I learn about QM the more I think that Copenhagen is not all that bad.

[@ditchweed2275]

Maybe we live in many worlds but think we're only in this one.

[@frrrmphpoo1700]

In the end our consciousness will only remember our longest timeline. Quantum immortality ftw

[@ditchweed2275]

Frrrmph poo can you elaborate?

[@johnmcntsh]

I like the saying " The universe does not care whether we believe or not, it is what it is"

[@0ptimal]

Really cool you were able to interview him. Awesome.

[@SleepToSound]

Love your content - thanks for taking the time to make them.

[@sorrowinthewind4258]

My favorite youtube channel by far, thank you so much for these super interesting videos ❤️

[@ArvinAsh]

Thank you. Glad you like them!

[@jordangoddard3376]

I read Sean Carroll's book not too long ago so I loved seeing this video! Carroll writes so well, I quite enjoyed the book and the many worlds theory, it's fun to think about. Hopefully one day we will find out the true nature of the universe!

[@smiling.buddha]

Excellent video with good questions and good explanation.

[@ReluctantStallion]

Wonderful, just wonderful. knowledge and curiosity is a wedge through the dark matter of uncertainty. Thank you for all the hard work and this channel.

[@ArvinAsh]

Thank you. Glad you enjoyed it!

[@mr.markusi]

I'm not sure why, but all your videos or of deepest interest for me. Like they were made for me. Would like to have some Videos on Quantumcomputing.

[@ArvinAsh]

I made one a while back on the basics of quantum computing. If you search on my channel, you'll see it. If you have a specific detailed subject on QC, let me know.

[@caryd67]

Thank you, Sean. And you, Sean. And you and you and you and you and you...

[@toughsoftieyogi]

6:51 That sealed the deal for me. I'm now a believer. Thank you for this very simple, yet convincing demonstration. I appreciate it.

[@Smrtcz]

So, there Is an universe in which I understand all this? Unbelievable 😅

[@Webfra14]

Only, if that is physically possible... This is "many worlds" interpretation, not "any worlds"...

[@manan-543]

Great interview Arvin. I hope for more interviews with people like Sean Carrol in the future. I had a question about the branching. Sean mentioned there are particles in the air that we don't keep track of. That's obvious because there are trillions of particles around us. But does a measurement made of a particle that we don't keep track of cause branching. In qm measurement doesn't require a conscious observer. So say there is a particle in superposition entangled with the environment as you mentioned. A photon collides with it and that's a measurement because it fixes the position of the particle in space. Would that cause branching? And are we also entangled with the environment? Would you make your interview public for all of your viewers cause I wanted to see the whole thing?

[@ArvinAsh]

To answer your question, according to many worlds, decoherence occurs when particles in the environment including the measuring device and us become entangled with other particles, and this causes branching.

[@rajamoorthy1969]

I absolutely love this concept of Multiverse. Cannot thank you enough for this video. I have watched multiple videos on this topic but your unique and simple style of explaining complex topics in such a simple and yet lucid manner makes this video a treat to watch. Thanks again

[@ArvinAsh]

Glad you enjoyed it!

[@garybalatennis]

Hugh Everett died at age 50, after a successful career as a government scientist, of a massive heart attack. He had lived for years over-eating and chain smoking. He, as the creator of the theory, believed and knew that there were indeed many branches or parallel worlds where a different version of him ate and lived healthy. So he basically didn’t care much about this one and his behavior in it. He lived a great life, he said, and he thought that he should “go out” the way he wanted to - enjoying himself. Moral of the story: Many Worlds of QM necessarily implies a landscape where you can jettison responsibility, accountability and morality. It’s a reality without “free will” or the exercise of it because all choices happen. Thanks by the way for the video.

[@GGoAwayy]

I thought about that moral question with regard to the Universe Splitter app. If you’re confronted with a difficult decision, rather than do the work to find the right course of action, you could just be lazy and say “well I’ll do both... in one timeline I’ll do this and the other timeline I’ll do that.” It feels like an easy way to evade responsibility for your actions. Hedging your bet across multiple universes.

[@rockestee]

Im so grateful you essentially explained what sean carrol was saying😂! Got lost a little there! I have sean carrols book, am a fan of his work, and really enjoyed this discussion. I normally lean towards many worlds, but now after watching i am back to being unsatisfied. I think there is some prejudice in our thinking that is blocking the solution to this, and an equally “elegant” ( your word -enjoy that descriptive Alvin!) theory awaits our realization. My idea is , we quantify “ nothing “being of no value, akin to hundreds of years ago the number zero had no value so they left it off the number line! and therefore all calculations were incorrect thereafter. It took a change in thinking to admit it had tremendous value! If memory serves correctly, some math experts at the time were killed over it! Bringing this memory to this current modern dilemma.... I wonder if nothing ( a three dimensional zero, if you will) was considered as having value, (as in no outcome is real nor measurable in traditional ways that make us comfortable) , a revolutionary theory will emerge. We have a prejudice towards physical being more real than emotional. But anyone who has ever stated all you need is love, knows emotions as real, if not more so then physical reality. What we know , so to speak, and what our current two options are saying are at odds in my view . Many worlds is saying ” real “ must be our origins, and origins is quantum mechanics.... (as our building blocks come from the atomic sized world). So many worlds asserts physicality times infinity is actually real. But what if our origins are “imaginary” .That our universe , its building blocks and laws, are there for discovery, measuring, and prediction, and joy of understanding... but, they are unreal, the way we think of dreams and feelings. Instantly able to morph and change and be everywhere at once. I am a classically trained musician by trade and have read many many books on quantum mechanics since 1991, and cannot communicate in formulas, please pardon, although i do enjoy people in your field giving me access to these formulas and explanations, so i can get the gist😂👍this is just my own hunch. scientists at one time liked nothing is real vs everything is real and now that is flip flopping, and i am glad actually ... but in my layperson take away... the nothing is real model assumed nothing was not a workable quantity. ( as in zero cubed) To believe every quantum decision has a real world counterpart well it might well not have bothered presenting a real face to us in the first place. Its prejudiced because it attempts to define what is actually real from our desire for what should be real. Arvin what is your 2 cents on my gut feeling that we are prejudiced against nothing ( again, redefining nothing =not the “absence of something” but “different than something”) because we prefer the realm of something ? Its uncomfortable to think the mother of all this physicality could be what we think of imaginary (and what i am saying is, the prejudice is that imaginary somehow equals valueless). Is it possible our current science has a prejudice preventing us from applying our formulas correctly? It seems to me this is the case. Now, back to a Bach fugue for me! 😊please dont say dont quit your day job, i beat you to it!😂

[@ArvinAsh]

Well put! It is not easy to accept the implications of the math solely on its face value.

[@rockestee]

Arvin Ash thank you👏👍

[@MaxMustermann-kf7fu]

You seem quite open-minded and deep-into-the-topic. If You can consider everything to be imaginary, Check out nondualism, IT may give You a boost on your journey to truth. Especially the channel "actualized" May be an inspiration for you, though the recent videos and Terms of language really built upon the long history of this chanel. Copenhagen interpretation and many-worlds are possibly both true AT once, but that needs a reconfiguration of what you define as "you". From an absolute perspective you experience all worlds simultaniously under all possible circumstances within the eternal here-and-now-reality. From the limited standpoint of an individual self reality must occur probabilistic and unknown until quantified measurement. Because the individual self is part of the whole, its measurements produce paradoxical outcomes like a dog who chases its own tail. Indeed, its a fractalized slice of the whole and therefore impermanent and per definition not omniscient (because limited) but entangled with the whole of reality (many worlds), which creates a strangeloop. By obseeving you limit the world to one possible outcome which is absolutely random/not predictable by you because you your self are entangled with it/creating it By imagining IT in the eternal here-and-now, where all possible worlds emerge from.

[@rockestee]

Max Mustermann thank you for your kind words and spot on suggestions. I will be sure to take a look. I am familiar with non dualism, and studied some eastern philosophy at the college level, and I do appreciate your insights and what you share above. And thank you for the encouragement! philosophy and physics are truly complimenting one another. I find it impossible at this point to not be inspired by it all!

[@Inteli9]

So we measure a particle and the "world", including us, branches? I am like John Snow, know nothing, but I think there's a huge gap in this logic.

[@xtratub]

binary logic have one outcome, but imagine logic with two outcomes and then world builded upon this logic

[@Qlerr]

this is an amazing channel. @Arvin Ash - thank you! this deserves more subscribers

[@ikariam12345678]

I did lsd and i experienced many realitys, i don't know how to describe it, it was the best thing in my entire life

[@LimbDee]

I don't know whether it is a comfort or torture that in one universe she will take my wrinkled hand one day and say: "we did have a wonderful life together, didn't we?" And I will reply: "yes my dove, we certainly had".

[@westbrook0853]

WTFFF

[@BenjaminBjornsen]

In one interpretation I have free wil for sure, I like that one :) Awesome video

[@ArvinAsh]

Haha...that may be the best way to choose a side.

[@mogenslysemose6757]

I have free will but my clones clearly took one ore more wrong choices! ;)

[@clavarx11]

I see ya, but you still have free will to choose from what is possible. So in one interpretation the possibilities are not running, but they "exist"(how would they exist if they dont exist yet), and the other interpretation , the possibilities are already set and running. Both would have the same possibilities and your choosing wouldn't be affected. You are still free to choose from the same pool. Your free will is safe dont worry.

[@BenjaminBjornsen]

@@clavarx11 : In a superdeterministic theory, no :/ absolutely everything is predetermined, or information travels faster than light(instantly to be precise). And we can't find evidence of local hidden variables :/ Learning this really bummed me out

[@capnam_12]

Great video! Very thought provoking.

[@thedeemon]

After reading Sean's book mentioned here, one crucial thing I don't understand about MWI is why do we perceive any change at all. The universal wavefunction evolves by the Schrodinger equation, and the only thing that's changing with time there is the probability amplitudes of different basis vectors, different "worlds". But since every observer is inside one of the worlds, they cannot see their world's amplitude, so they cannot see anything change at all. E.g. when a ball moves from left to right the way QM describes it is the world with the ball on the left loses its amplitude while the world with the ball on the right increases its amplitude. However within each world the ball stays where it is, the only thing that's changing is this branch's amplitude. We seem to somehow travel from one "world" to the other as time passes, but that's not described by the MWI.

[@ArvinAsh]

You make a very good point. The reason that the idea of "decoherence" has come to be may be to explain our observations. But why we experience the universe as seemingly classical is something that, at its core, the theory may not address. If Sean is reading this, I hope he responds.

[@ronaldallengonzales6122]

Hello Sir Arvin Ash, can you please discuss about infinte mirror, whats the scientific mystery about infinite mirror, it feels weird. Thanks and more power.

[@leethomson5733]

Hello, infinite mirrors do not exist, Goodbye 👋

[@RaddDronzy]

It can also mean that the universe is a simulation and the pixels behave differently when we observe them since the cpu running the simulation have to do extra work.

[@clavarx11]

You know what makes the cpu slow? a lot of information/instructions at the same time. You know what makes time slow down? Gravity. So a black hole consumes all the processor, and things starts to run slower there until it stops. Then you have to kill the process, because the program stopped working lol

[@SuperOlivegrove]

As always, a very inspiring video with some interesting points 👍

[@songckim]

Great piece and interview!

[@mrloop1530]

In another universe the emperor might wear some extravagant clothing. In this universe he wears nothing.

[@bdayapraar6673]

The possibility of outcomes collapse when the wave function collapses thus rendering the many worlds theory untenable. The previously available outcomes do not assume a life of their own and create a multiverse, they were simply options that were once available that cease to exist when not triggered. Very similar to the concept of procedural generation.

[@ArvinAsh]

If you buy the Copenhagen interpretation, yes. But if you buy the many worlds interpretation, then no. This is the argument that Sean Carroll makes.

[@ihsahnakerfeldt9280]

>cease to exist when they're not triggered No. MW specifically argues that they do continue to exist and continue to branch off but are inaccessible to us (due to decoherence). That's the entire point. It only looks like a probability collapsing into actuality because the other outcomes are not accessible to us.

[@PazLeBon]

so you could throw a 6 on a dice but you now didnt throw a 1,2,3,4 or 5 therefore those are alternative realities. Pmsl what a serious waste of brain hours. Scientists, pahh y'all becoming as useful as politicians

[@CaptainPeterRMiller]

Another great video from Arvin Ash. Maybe I am still confused but differently informed. Great.

[@bobbyrobmaxey]

Great video. I've nearly finished reading Sean Carroll's book about the many worlds theory, and this video encapsulates the core ideas in a very accurate and succinct way

[@ArvinAsh]

Glad you enjoyed it! That is a good book. I had Sean review this video before publishing it to make sure I wasn't misrepresenting anything he said.

[@jimtroeltsch5998]

I swear the last time I watched this video you ate the apple...I'm like 99% sure

[@ArvinAsh]

Haha.

[@NishantKJha-qk2ow]

Does this mean.... I am present everywhere and doing everything thing (if I sum up all the different world possibilities of my whole life.)?

[@ArvinAsh]

In a manner of speaking, but as Sean explains, it is a version of you, not you exactly.

[@marxug1]

It would be interesting to see a “Hilbert map” of a person’s life - a graphical representation of all possible life paths from birth through death. Of course it could only be imaginary...

[@KingaGorski]

Soooo fascinating! The identical twins analogy is really useful in helping wrap my head around the MWI.

[@xe2ac]

Great video! Thanks for sharing knowledge

[@ArvinAsh]

Glad you enjoyed it!

[@anwarulmamoon4299]

Mr.Ash can you answer me? If many world interpretation is true,then if some one dies in one world, is his duplicate still alive in other world?

[@ArvinAsh]

Yes, there is a universe where he would still be alive. Keep in mind that impossible things can't happen. If someone was alive 200 years ago, they wouldn't be alive in any version of the current universe.

[@LuisAldamiz]

Or died earlier, or turned immortal... it's such a weird conjecture: all possibilities that have non-zero chance happen.

[@mogenslysemose6757]

@@ArvinAsh interesting, if every year you have a nonzero chance of surviving another year, then in some Multiverse instance you get 200+ years old.

[@soldierofitaly3663]

Event that have 0 probability of ever happening don't happen in any branch of Many Worlds

[@hahtos]

After reading Carroll's "Something Deeply Hidden", I have to say that I have shifted to see the many worlds interpretation as the most natural and complete description of QM without any arbitrary postulates about wave functions and observers. Interesting to see if he can form a quantum theory of gravity (he is working on that) using the principles he describes.

[@Webfra14]

Indeed. I thought many worlds was lunatic. After reading his book I think, to not at least consider it, is lunatic. Why add a seemling arbitrary rule to the system (wave collapse), when the equation everyone uses (Schroedinger) already contains everything needed to "explain" reality. It even makes it plausible, why we don't "see" the other branches. If the universe really branches, so be it, who am I to not like it... If not, it still is a simpler theory to work with...

[@duprie37]

But that's the whole problem. Observers exist. _We_ exist. A human consciousness, an observer, wrote down the Schrödinger equation in the first place. An explanation that is mathematically neat but functions as nonsense as far as it concerns us versus the real world is not a very useful explanation. Sooner or later we're going to have to include subjective consciousness in our scientific musings. After all, subjective consciousness is what realizes maths and science in the first place.

[@baibhabmondal1740]

Love your content!

[@Boogieplex]

Great video Arvin! Awsome to see you interviewing Sean Carrol, he’s an “A lister” in the science community! While I respect Sean Carrol,and he is impossibly more intelligent on this subject than I.....i think there’s a more elegant answer that is still eluding us.

[@ArvinAsh]

Well said! That is my intuitive feeling as well. MWI can't be the final answer, just like Copenhagen interpretation can't be the final answer. That's just my opinion, of course, I could be totally wrong.

[@adbell3364]

Interesting. The first question was, specifically "how?" and he dodged that with an answer explaining "when" and "why".

[@LuisAldamiz]

He's become a total cheat.

[@gkillmaster]

I'm serious that LSD trips seems to correlate with this. I constantly experience this sort of fading copies or fanned out card feeling of me and my surroundings. Like I'm in this ether of rapid copying like movie frames in a projector but smeary. I know It's most likely a woo woo long shot but it does make me wonder if there any possibility at all that in that state you can somehow perceive your own entanglement and decoherence as a quantum being to the quantum world. It is strikingly reminiscent! Thougt it seems like a constant continual non-fluctuating cadence and I would think that entanglement happens more randomly.

[@GGoAwayy]

I don't think so in terms of real perception. But maybe it helps you conceptualize a difficult idea. Think what is actually happening when you take LSD. You still have the same material brain, its just getting different results than usual. You dont physically develop a new sensory organ that can perceive new realities just because you took LSD (anymore than if you had caffeine). Your thinking is temporarily changed, but even if your consciousness is processing different information in a different way, its still limited the same way in terms of its sources of information. But it could definitely help visualize a difficult concept that was hard to grasp normally.

[@michaeljoefox]

Man you gotta hook it up, since covid hit the tabs dried up.

[@vantablacknl]

@@michaeljoefox same

[@captainzappbrannagan]

Schrodinger equation can't be denied, but I'm betting the many worlds are actually just infinitesimally small plank length dimensions that actually collapse out of the probability spectrum instead of creating new branches, all alternate possible branches collapse. It is tricky though as what is intuitive or what we want to believe is real reality, bears no care of what is reality. I think we have to go by math on this one, but explore other equation interplay in the branching spectrum. A very fascinating topic and you hit the important questions, thanks for sharing!

[@abhishekdey9717]

Arvin you are magnificient as always, A true admirer of your content. Kindly make more videos on such quantum entanglement stuff. 👍

[@ChopperSouthern]

Why waste money on an app when you only need to toss a coin??? I don't get it!

[@ArvinAsh]

Great question! The tossing of a coin is not a quantum event - it will not directly split the universe in two. You need a true quantum event to split the universe.

[@ChopperSouthern]

@@ArvinAsh Hmm - I get it now - I think - it's kind of hard to wrap ones head around! Thank you!

[@LuisAldamiz]

@@ArvinAsh - The tossing of a coin is a quantum event at its deepest level: everything is quantum-mechanical: lots of photons, electrons, gluons and quarks were involved at extremely high levels of quantum uncertainty in that coin tossing.

[@mogenslysemose6757]

@@ArvinAsh can you prove it is Not a Quantum Event? It might end up depending on uncertain locations of atoms on the table and uncertain impulses of atoms in the coin....

[@rustyshackelford3934]

You’re the two dimensional being, attempting to conceptualize the 3D object that just passed through your reality. These things that are inexplicable, except through ornate flights of fancy, will become clear only from a higher dimensional perspective.

[@glennward5898]

Niels Bohr 1885-1962 Physicist, Philosopher Won the 1922 Nobel prize for his research on the structure of atoms "The fact that religions through the ages have spoken in images, parables and paradoxes means simply that there are no other ways of grasping the reality to which they refer. But that does not mean that it is not a genuine reality."

[@rv706]

I think the most confusing thing about the many worlds interpretation is that it's presented as if this "branching" process was a discrete phenomenon, occurring at certain given moments in time. If this was the case, then many worlds wouldn't be any less mysterious than Copenhagen. *But*, according to the MWI, the branching isn't a discontinuous, instantaneous, process: it's continuous, as governed by the Schroedinger equation. Even the notion of "a universe" (or "a world") isn't sharp, but approximated: the mataphor by Sean Carroll about twins continuously evolving from a single egg into two persons seems very apt (about this aspect). In fact, the only thing that occurs, during measurement (or most interactions with macroscopic systems), is the state vector of the universe smoothly transitioning from a separable state to an entangled state (relative to the tensor product factorization of the Hilbert space of the universe into that of a given system and that of the remaining environment). The more the state vector is close to the initial separable state, the more we feel like saying there's *one* world; the closer the state vector is to the final entangled state, the more the universe is *split* into many worlds: one world for each "pointer state", i.e. eigenstate of some special observable determined by the environment.

[@lucidzfl]

Great discussion but I don't like Seans answer. Saying "it adheres to the schroedinger equation" is basically using an untestable theoretical multiple universe and saying here, the math works. How is this not a magic number? Further what stops me from saying, we are in a simulation. Quantum mechanics is nothing more than the return val from an rng. If its fundamentally untestable then its ability to fit a math formula seems useless

[@ArvinAsh]

You make a good point. In his defense, Sean is saying that he is interpreting the Schrodinger equation in its purest mathematical form. And this equation has been proven to be spectacularly successful in making predictions. So in a way, that is the the "proof" he is trying to show.

[@luisdiegocr]

Well, I guess I'm happy to be in the universe branch where this KZbin channel will continue "unsatisfied" until the truth is discovered. Poor suckers in the other branch where the KZbin channel just gave up on the subject. 😂🙄😳

[@dennistucker1153]

Excellent video! I would tend to believe more in the "Many Worlds" interpretation. I just don't think there is enough evidence to be sure yet. On the use of the term "branching" like our universe branches, this seems to imply that some other action occurs when a quantum measurement is taken. Why must there be any other action? Who's to say that there isn't a pre-existing infinite set of parallel universes that were there all along?

[@ArvinAsh]

That's an interesting take.

[@avejst]

Thanks for sharing👍😀

[@cowdog3940]

The worlds he envisions are created by his mathematics. It should be the other way around.

[@UmVtCg]

Something is mixed up here, I watched you eat a lollipop.

[@samuelpope7798]

There is simply no guarantee that a deeper more satisfying truth is or ever will be accessible to us. An interpretation that is based on elegant math may prove useful even in the absence of a of proof. Granted the time to believe something is when there is sufficient evidence for it in fact being the case. At the same time I don't necessarily "believe" that two parallel lines never intersect but I am willing to make that assumption when doing geometry because it is useful.

[@loganwolv3393]

What i don't quite get about quantum mechanics is how did they figure out that an electron (or any other particle) can become a wave (or go in superposition? Like to notice that you need to measure it right so how isn't that impossible? sounds like some paradox.Hope you can answer this :) Great vid btw.

[@carbon_no6]

It’s all contained within our universe. Splitting off is a kin to just sweeping the dirt that was just swept up under the rug and saying it’s clean.. it may not leave any uncertainties like the Copenhagen Interpretation, but you’re merely swapping one possibility and replacing it with the same issue just changing the uncertainties specific to that explanation. You don’t see the quantum processes on a macro-scale because at this scale there are too many chances for a vast multitude of measurements to be made by just being present within proximity. If stands true about a “measurement” only needing to be made by another object and isn’t bound by conscious-observations then any inanimate object can add its measurement to the total and this gives us our perception of the micro-scale, but in the macro-scale. This is a repeating process.

[@jamal2558]

i love your videos.. keep it up

[@mraghav93]

How on earth he has only 250k followers? He deserves at least a couple of million subs.

[@gogogravity]

The series DEVS opened my mind up enough to consider the many worlds theory as viable. It was just too weird for me to wrap my head around it. I am on board now.

[@Webfra14]

Welcome on board! Enjoy yourself and take a seat, there should be many free. If not, we can just branch a bit harder to make space :)

[@shaunpearse7236]

Long-time many-worlds supporter here. I think it makes a lot of sense and isn’t that difficult to imagine the universe replicating every instant. There’s more bizarre things in physics in my view. I recommend Sean Carroll’s book for physics in general.

[@angeldude101]

I don't even think of it as the universe replicating, so much as a bubble that expands away from the decoherence at the speed of light that contains both branches, and that elsewhere in the universe there are completely separate bubbles with no overlap but will eventually overlap once they get big enough, and the intersection would effectively contain 4 branches even if the rest of the bubbles only have their original 2. And of course the entire continuum of possibilities from a quantum event exists in those bubbles with the rarer outcomes having a lower amplitude, rather than just 2 branches of equal amplitude.

[@NZESP]

If I allow myself to attend to what might be satisfying, then the notion of near infinite realities arising deterministically noses ahead. Putting personal preferences aside, the maths seems to have Everett pushing ahead of Bohr. Thanks to both of you - great work!

[@acemanNL]

Arvin, I saw you eat the lollipop... Did I branch too or do I need a stiff drink my friend? Great video as always! Thanks.

[@ArvinAsh]

Haha, you are visiting from another dimension, if you did.

[@phoule76]

I like it when Sean points out that no one truly believes that the Copenhaguen interpretation is the final answer, yet students are taught not to question reality beyond that. It seems ridiculous!

[@ArvinAsh]

You don't like Feynman's "shut up and calculate" idea either?

[@phoule76]

@@ArvinAsh I suppose Copenhaguen was agreed upon (and thus takes its name from the city where this agreement happened, rather than anyone one physicist taking credit/blame for it) in order for Physics to be able to "move on" and work on more testable hypothoses, but it sure is annoying and fascinating all at once!

[@Flyanb]

So many worlds is a feel good way for some scientists to get around super determinism? It’s still deterministic? Right? But not because every possibility that could happen does? It’s sooooo complex. I feel like KISS tells us super determinism is better? Thanks for the video! But, I don’t think we are any closer to the truth and my mind is still fried.

[@pieexpo140]

i really like your videos. can you explain graser, vacuum boiling and talk about 40 unsolved problems in physics

[@alecplano9563]

The acceleration of the universe is just all the new universes popping into existence pushing us outward.

[@LordandGodofYouTube]

I love your videos.

[@amandavelloen2871]

Love your interpretations! It makes sense! The truth will set us free...

[@rw6836]

I think of position of an electron as akin to position of a dice in mid-air. Measuring position of an electron collapses into a definite position, just like the dice hitting a surface and settling into a number facing up. I think "many worlds" is not required to understand or explain how that works. Before something happens, there are possibilities. After something happens, there is a definite branch taken. That doesn't mean that all possibilities have to had happened somewhere in the "multiverse". At least, that's how I think of it. "Many worlds" seems like human thinking trying to figure out what happens, as opposed to observing that possibilities collapse into definite branch.

[@rossdavis5833]

To answer your question about which interpretation is least bizarre, I would say it's the one that doesn't contain a massive hand wave around the collapse of the wave function. The Copenhagen interpretation is effectively giving this as its final answer: "Yeah, some sort of hocus-pocus happens around observation and measurement." And if one asks for a contextual definition of observation and measurement, then the reply is, "I don't know - who cares?" I am not physicist, but as a casual "observer" I much prefer Sean Carroll's argument for Many Worlds which at least has a logical explanation for what in the world(s) is going on under the hood.

[@ArvinAsh]

I understand your point. But I still object to the branching in many worlds. I just don't see where, in the equations, it shows branching occurring. It is like saying every time I toss a coin, since the probability is 50/50 I will toss a head and tail, Two different versions of me toss each probability, and in two different versions of the world. I don't think mathematical probability implies that all probabilities occur somewhere anytime it is probable. I could be wrong.

[@harshad761977]

“Universe is expanding, but there is no container?” Fish think water is the only world and there is nothing like water container. Can we think of world or void without spacetime as a container? Spacetime evolved after Big Bang. There was no time and space before that event. But still can we imagine supersets of our spacetime. It might be the case that our spacetime is just one thing among many different entities/properties of that supersets.

[@ArvinAsh]

The presumption is that space time was born at the Big Bang, but the truth is that we have no idea if that is the case.

[@harshavardhan9399]

you guys are completely wrong about the big bang theory. big bang theory just tells about the formation of stars and planets from the beginning. but doesn't tells about the formation of space and time. big bang is just an event after the formation of space and time

[@tommyvictorbuch6960]

I got enough troubles in this Universe, thank you very much.

[@H1kari_1]

Me, as someone who endorses determinism (even superdeterminism) and doesn't believe in free will, the many worlds theory just sounds like a lazy workaround for figuring out quantum mechanics. There is just too much that is almost impossible to prove. The mirror in that lab probably has structural characteristic that made that photon take a certain path at a certain time/angle.

[@LeViIain]

I'm no math expert but I know that you can create equations that work on paper but fall apart when tested in the real world because there's something you didn't take into consideration. In other words, you can't know if your equation is complete until you tested it in the real world. So without physical proof of a parallel universe, you might not be able to prove that the many worlds theory is incomplete, but you also can't prove that it is complete. I don't mean no disrespect and I'm most likely wrong, but this theory feels like they just took the problem elsewhere, "completed" the Copenhagen theory, and call it a day.

[@xtratub]

good point about math equations, all equations already existed before we discover them, just mix-combine math symbols on paper and you get some equation, which may be solvable or not. and some of this equations have common parts, just like worlds in many-worlds.

[@GGoAwayy]

"Should the universe be interpreted strictly on mathematics?" Sounds like a good time to do an interview with Max Tegmark about his many worlds book "Our Mathematical Universe". For me, I have no idea how ANYONE finds the Copenhagen interpretation a satisfying answer on any level. Seeing a "measurement" as a "discovery" (as in, discovering which reality youre now in) makes much more intuitive sense. What if Schrodingers cat had a flea that observed the vial of poison breaking? Interpreting measurements themselves as collapsing a wave function is as unsatisfying as just believing in magic.

[@ArvinAsh]

Not sure if any interpretation of QM is really "satisfying" in any way. They are all likely incomplete.

[@1stFloorSessions]

I fell asleep during this video, when i woke up i still had all the knowledge about it. Guess i found out how to merge. Handy stuff!

[@krkivukicevic]

"Is there a deeper truth that would be more satisfying?" Truth is under no obligation to satisfy anyone.

[@ArvinAsh]

Yep, absolutely right!

[@contactkarthik1239]

I have to watch many times

[@omidkhodaparast7633]

Hello Arvan, I was wo wondering about the electton example that u put forward. If an electron causes decoherence at some point, can it again cause decoherence later on in the universe?

[@rodrigoserafim8834]

Great of you to have a talk with Sean. I really don't like the "branching" part because it creates an exponential number of universes. It seems a bit too "human" way of thinking. If I knew any of the math involved I would guess the result looks more like a continuous quantum amplitude in that there is only one block of multiverse and parts that get entangled and disentangled in between "layers". Of course, so there isn't a "top" and "bottom" layer the amplitude dimension just circles around. That would explain the use of complex numbers in the wave equations, and also possibly give a testable theory, since with "branching" the split universes never meet again, while in a "block multiverse" there might be some type of entanglements that split out but then come back to the same sheet. Just throwing science at the wall here to see what sticks. One thing I would have liked you asked was if there is some relation between the average rate of entanglements happening in a system and time. I.e., if its time that triggers the quantum effects to happen at a certain rate, or if instead its the probability of certain events to happen compared to others than give rise to the perception of time. If all event in the universe where to happen twice as slow, would we even know the universe is slow? From our perspective to Earth would continue to take exactly the same time to spin compared to how we measure quartz oscillations or any other kind of clock. Anyway, great work Arvin. Kudos.

[@MagusPerde42]

There's an interesting question about many worlds that I wish you had asked: how many "many worlds" are there? "An infinite number" would appear to be the glib, easy answer, but why? Couldn't it be that statistically all the potential outcomes of every decoherence event converge on each other? Many of the "many worlds" would be virtually identical so why couldn't the identical energy (including energy in the form of matter) be "shared" among all universes it's in. There's no dark energy or dark matter, simply that there's a portion of the "container of many worlds" that projects into a particular branch that is perceived as real matter and energy while the portion that doesn't has "dark" functions. But there's really just energy but only part of it projects into our branch.

[@ArvinAsh]

I asked that question in the full interview with Sean. It's on the channel if you want to look it up.

[@MagusPerde42]

Arvin Ash another question I have is if universes are waves, do they have phase? Polarity? What happens if two universes are out of phase with each other?

[@maurosanchezhernandez5021]

Arvin. another explanation of QM will be Superdeterminism, the measurment of the particle reveals information that was "in there"" since the beginning of the Universe, the measurement in reality is a unveilment and the value was predetermined and my wish to perform the experiment in order to know the value was also predetermined!

[@chriswalker7632]

Cheers. I was searching "what is the average entanglement of the universe" when I came across your channel. So I thought I'd check out this video. You seem to know a lot more than I do. Both Einstein's and Newton's equations of gravity use a squared relationship - they are power laws. Something else that has a power law is network relationships - for example the size of the population, say 8 billion, is related to the avarage number of friends each person has, say 26 friends, by a factor of 26 to the power of 7. Where '7' is the degrees of separation of one individual from another in society - i.e. it would take an average of seven connections between myself to yourself. At least that's the theory. This relationship can also be represented I think using a 'Pareto Law' where instead of using the whole numbers '8 Billion' and '26 friends' you would instead using a fraction of '1' - for example 0.79654 to the power of 7 is 0.20345, and here both these numbers add up to 1. They'd have basically an '80/20' relationship as a pareto law in effect. I wondered if a similar thing was going on with gravity? - if there was a networking method of representing the effects we see? I've seen some theories that use a networking method to try and bridge the gap between quantum mechanics and relativity, but I'm not qualified enough to critically evaluate them. But for example with the power to the 2 law you have with gravity, then this would be like a pareto law given by the golden ratio (as 0.61803 to the power of 2 is 0.38197 - and both these numbers add up to 1). So I was wondering if there was similarly to what I started with of the example of the world population relationship to the number of friends people have, if there was a relationship to the number of particles in the universe and the average amount of entanglement per particle - it seemed to me that gravity, particularly with something like a black hole, increases entanglement (along with entropy). In much the same way you could have a group of 16 people, with an average of 4 friends each (4 to the power of 2 is 16) - but maybe there is a close group in those 16 people that have more friends each while outside of that group there are those with less friends each (but still an average of 4 friends each for the whole of the 16 people). Maybe you could have a system of 16 partcles, with a concentration of very entanlged particles while other particles are hardly entangled at all (but still on average there could be 4 entaglements per particle - so that would be 4 to the pwer of 2 is 16). And in much the same way you have stronger gravity around a planet where particles in space are more entangled compared with further away where particles could be less entangled - perhaps to a power law like Newton's or Einstein's. LOL - no worries. People have these ideas...

[@lepidoptera9337]

You can tell that neither Sean Carroll nor Arvin Ash ever read Everett's dissertation, or they would have noticed that he made a trivial rookie mistake in his second sentence. I take that back. That mistake already invalidates his first sentence. ;-)

[@saadkarim81]

Good video

[@cacnus]

The video came out 1 minute ago... It's 17 minutes long

[@humbertojimmy]

Some people have a hard time believing that one single event can be interpreted in 2 different ways *while both* are equally correct. They claim that something is either A or B but not both at the same time (law of identity). But if we look at the ballerina optical illusion [check KZbin] we get exactly that. Once the ballerina is set in motion, and *without* ever changing her spinning direction, we are asked if she's going left or right and *both* answers are correct at the same time. The interpretation is choice free, you can see her going left AND right, and either answer is correct.

[@ReallyStrongGuy]

What are the seals/emblems in the graphics at the end of the video?